Simple Guide to the Raspberry Pi GPIO Header - Raspberry Pi Spy
40 Pin GPIO Extension Cable for any 2x20 Pin Raspberry Pi [150mm / 6 long] : ID 4823 : $2.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Amazon.com: Mini Base Board for Raspberry Pi Compute Module 4, with Standard CM4 Socket and Raspberry Pi 40 PIN GPIO Header, Onboard Multiple Connectors, Suitable for Compute Module 4 Lite/EMMC Series Module :
Amazon.com: 40 PIN GPIO Header Adapter Color-Coded Header Expansion Board for Raspberry Pi 400,Easy Expansion : Electronics
Raspberry Pi 40-pin GPIO Short Pin Expansion Header - Spell Foundry